Sharpening device for chalk.



SHARPENING DEVICE F08 CHALK APPucAnom m2o oc. 31. me.

llwlf, Meme@ @mz/1 MICHAEL J'. ROSS, OF ROCHESTER, NEW YORK.

SHARPENING DEVICE FOR CHALK.

Specification of Letters Patent.

Patented Nov. 27, 19t t'.

Application led October 31, 1916. Serial No. 128,695.

To all 'whom t may concern:

Be it known that I, MICHAEL J. Ross, a citizen of the United States, and resident of Rochester, in the county of Monroe and State of New York, have invented certain new and useful Improvements in Sharpening Devices for Chalk, of which the following is a specification. y

The present invention relates to sharpening devices for chalk employed by tailors for marking on cloth, and an object thereof is to provide a simple and inexpensive instrument which will operate simultaneously on two marking edges of the chalk without causing the breaking of such edges.

To this and other ends the invention consists of certain parts and combinations of parts all of which will be hereinafter described, the novel features being pointed out in the appended claim.

In the drawings Figure l is a sideview of the instrument showing the manner in which it coperates with two opposite edges of the chalk;

Fig. 2 is a perspective view showing the manner in which the Sharpener and the chalk are supported in the hands during sharpening; and

Figs. 3 and 4 are detail views showing modifications of the invention.

At the present time, the method in general use for sharpening tailors chalk is to scrape the opposite faces of the two edges one after the other by a penknife. This requires a certain skill to produce a perfect edge and, at the same time, this method is slow. Machines have been designed which will operate simultaneously upon two faces of a single edge. However, such machines are not only eXpensive but have been found to produce a ragged or broken edge, owing to the fact that the marking edge of the chalk is engaged.

According to this invention, a Sharpener is provided which operates simultaneously upon one face of the two edges so that the extreme marking edge is not engaged upon opposite sides simultaneously. The sharpener has its two scraping edges so arranged with reference to the handle that the chalk and the Sharpener may be held in natural or easy positions in the two hands so as to the two scraping operate upon one face of each of the two marking edges.

The Sharpener comprises a handle l with a blade 2 arranged with its length alined with the length of the handle, the blade having two scraping edges 3 and 4E lyinff at acute angles to the length of the blade and at an obtuse angle to each other, the edge l lying at a slightly greater angle to the length of the blade than does the edge 3. W'hile the two edges 3 and 4 meet at a point 5, in the embodiment shown in Figs. l and 2, it is apparent that this point need not be provided but that a separate scraping edge may connect the two edges 8 and t, as shown in Figs. 3 and 4, the edge 5a being parallel with the length of the handle in Fig. 3, while the edge 5b in Fig. l is curved.

Owing to the shape or form of these marking chalks, the natural tendency is to hold the same by engaging one end thereof with the thumb, and the opposite end with the forefinger and the middle finger, as shown in Fig. 2, causing the chalk to have that end which is engaged by the thumb in a higher plane than the one that is engaged by the forefinger, while the edge of the chalk over the palm of the hand is lower than the edge of the side of the hand. The natural or easy position for operating upon a chalk so held is with the upper part of the arm at the side of the user, and the forepart arranged to swing on the upper part as a fulcrurn. This position of the knife is substantially like that shown in Fig. 2 of the drawings. In these positions of the chalk and the knife, edges 3 and et operate on one face of each of the chalk edges. If the two edges are arranged at the same angle to the length of the blade, then with the natural or easy position of the hands holding the knife and the chalk, the edge nearer the handle would not contact with the chalk while the other edge would bear with greater pressure upon the chalk and tend to produce an uneven edge like an ordinary penknife.

From the foregoing it will be seen that there has been provided a scraper which will operate simultaneously on one face of each of two chalk edges with an even pressure so as not to produce an uneven edge, the

knife being so constructed that natural or with its length alined With the length of the easy positions may be assumed by the hand handle and provided with two straight l@ of the nser Ain holding the chalk and the scraping edges forming anA obtuse'angle beknife. A tween them, the edge of the knife nearer the 5 What I Claim as my invention and desire handle being at a greater angle to the length to secure by Letters Patent is f of the blade-than the other.

A sharpening device for tailors chalk i l comprising a handle, and e blade arranged j 1 MICHAEL J. ROSS.

Cypiefs of this patent may be obtained for ve cante each, by addressing the Gommissonety of Batentrs, Washington,D. C. 

